Tape perforator



June 4, 1940. J. A. SPENCER 2,203,582 Y TAPE PERFORATOR' Filed May 14, 1938 mo oo Eo u z 00:0 E 09:0 l A.: oo a ,E Q v! :ooo

om/fa 4r pos/nous f, 3,4 Fon INVENTOR'.

ATTORNEY.

vPatented June 4, 1940 TAPE` rERFoRA'ron James A. Spencer, Teaneck, N. J., assignor yto Radio Corporation of America, a corporation of Delaware Application May 14, 1938, Serial No. 207,884

` 6 claims. (01.164-112) `This invention relates to tape perforators as used preliminary to automatic printing telegraph code transmission. The invention has more particularly to do with apparatus which is adapted to perforate a transmitting tape in a suitable manner for use in a so-called '7-unit code system.

`shown having a uniformity in the number of marking elements.

,57,7% The `reason for maintaining uniformity in the number of marking impulses in a signal, and hence the same uniformity in` the number of perforations arranged transversely of the tape, is that this system lends itself to error detection 2 at the receiving end. A receiving printer has been constructed which properly responds to uniform length code signals only when the number of marking elements of the signal is normal. Any abnormality in the signal reception incident to the introduction of static impulses or to the dropping out of impulses for any reason results inthe actuation of an error indicating typebar in place of the type bar for the intended character.

It is an object of my invention to provide a keyboard-operated tape perforator which will at all times operate to perforate in the tape a fixed number of holes representative of the marking elements of a uniform length code signal.

It is another object of my invention to provide certain modifications and improvements of a keyboard tape perforator of any one of a number of well known types suchv that '7-unit code signals may be set up in the form `of perforations for determining thecharacteristics of a uniform length code signal having a total of seven marking and spacing elements. i y The invention will be illustrated and described hereinafter by reference to the accompanying drawing, in which 45 Figure 1 `shows schematically and in perspec- 1 tive a few of the mechanical elementswhich in combination serve toV link the keys of a manual keyboard to the punches withinthe punch block offa perforator; v i i 50 Figs. 2u, 3 and 4 show, respectively, different arrangements of `notched `code selector members suchas may be attached `to different keybars of a keyboard for actuating the punch control mechanism; and

5:5A Fig' shows illustratively a piece ofperforated factured by the Teletype Corporation.

tape `bearing perforations representative of the various code combinations to be used for the alphabet, figures, other characters and functional signals. i

`The embodiment of my invention as herein i1` lustrated and described should be understood as merely illustrative since the invention itself is adaptable `to other types of tape perforators. The specific form of perforator in which the invention is herein exemplified iswell known in the art andhas been described in a book entitled Printing Telegraph Systems and Mechanisms by I-I. I-I. Harrison, published by Longmans, Green 8i Company. On page 167 of this book is a brief description of a similar known keyboard perforator, reference being therein made to Fig. 165

` on page 166. That was a perforator of the socalled "Morkrum system. The apparatus with certain refinements of construction is now vmanu- My improvements will now be described in detail. l

Referring toFig, 1,1 show therein a keybar il] which is only one, `of course, of the entire group of keybars of the keyboard. This keybar is pivoted at Hand carries a code selector comb l2 which may be afxed thereto in any suitable i manner, as, for example, by rivets I3. The selector comb may, however, be welded on, if deshed; or in certain `instances it might be formed integrally` with the keybar. Beneath the comb l2 is an arrangement of loop bails P and l to l inclusive. The bail 'P is actuated by each and every key and has theiunction of `closing the contacts of a switchfor electromagnetically driving the punch hammer and the tape feed device. The remaining loop bails l to l. inclusive serve `when they are actuated for disengaging their respective punches so that no corresponding holes The mechanical linkages between the bails and the punches include upwardly projecting lever arms i4 which are integral with the bails l to l. The upper end of each lever arm iii is notched to form a yoke for carrying the tip end of a bell crank It. Seven of these bell cranks `I5 `are mounted one `over the other on a vertical' pivot post I6. The forward ends of the bell cranks are pivotally connected at Il to control arms I8. These control arms extend within the assembly consisting of dieand stripper plates, punch block, guide plate, shedder, and shedder wearing strip shown generally at I9. The detailsof construc- 55 of them stand above and four below a preferably smaller punch hole 2U the purpose of which is to punch a continuous row of sprocket feed holes the tape. The punch which perforates the sprocket feed holes in the tape respondsalways` tothe actuation of the punch hammer and the latter respondsto the actuation of thev bail -P by each of the keys.

According to the practice of the prior art, the

tape is fed past the punches one step at a time in response to each return stroke actiony of the punch hammer. The `tape feed device is not new and has not, therefore, been shown herein.

In order that the improvements comprehended in my invention may be better understood, I have shown by way of example, three of the selector combs I2 in the three Figures, 2, 3 and 4, respectively, where each of these combs is adapted for Ause in punching a permutation ofA three holes inthe tape indicative of the letter or character to be transmitted. In Fig. 2 the code signal forthe letter E is represented by a notched formation in positions 4, 5 and 6. In Fig. 3 the letter Z is symbolized by a notched comb wherein the notches occur in positions I, 6 and 1. In Fig. 4.- the notches of the comb I2 represent the letter F by being located in positions I, 4 and 6.

Theremaining permutations to be embodied in the notched combs I2, which are attached to the keys Ill; may be readily understood byreference toFig. 5. Here there is shown a length of tape which has been perforated with all the different code combinations required for transmitting the alphabet, the figures, the usual punctuation` marks` and other characters shown on an ordinary typewriter keyboard and certain functional signals, which are required especially in telegraph typewriter systems. These functional signals usually include a letter-shift signal, a figure-shift signal, a space and a bell. The receiving printer is adapted to ring a bell in response to the reception of a certain code signal which must always follow the figure shift signal. The bell signal may correspond with that of letter S, or letter J, if preferred.

In the Aoperation kof my invention a message to be transmitted is perforated on the tape by.

ordinary manipulation of the keys of the keyboard. It will be noted, however, that each and every key, except the blank key, serves to punch three code designating holes, no more, no less. The fourth hole which is very slightly offset from the center line of the'code designating' holes is merely a sprocket feed hole. This sprocket feed hole is punched not only inV response to the actuation cf every character key, but also by the blank key. Consequently the selector comb I2 which is attached to the blank key has no notches therein In the absence Yof notches thepunch hammer magnet and the tape feed devices are actuated, but .no code designating holes are Referring to these positions'by numf ber from the top down, it will lbe noted thatthree.

punched. This blank key can be used for feeding out a certain length of tape sufficient so that, when the message-perforated portion of the tape is torn off, a reasonable length of blank tape will remain beyond the message perforations. Another device for punching the: feed holes while feeding blank tape is also embodied in the conventional perforator and is more rapid in operation thanthe single-Space'action of the blank key. Such a device, however, is not new and has not been shown.

It will be understood by those skilled in the art that various modifications of my invention maybe adopted without departing from the spirit thereof.. The scope of the invention itself is,

therefore,I defined by the claims to follow.

I claim: l. In a keyboard-operated tape perforator, a

, plurality of key bars sufficient in number to individually represent the letters of the alphabet and other characters, at leasteight bails underlying the key bars, tape punching and feeding mechanism operable under control of one of said bails by depression of any key, and meansV including a selector comb mounted on each key bar and each permutationally and distinctively notched to avoid engagement with exactly three of the bails appropriate to selected positions in` which code-designating holes are to be punched,

said means'serving also to depress the remaining bails in response toI a key depression, whereby blanks are left in` the tape in non-selected furtherl characterized `in that each one is suit# ably notchedk for avoidance of vengagement with exactly three of said bails.

3. A set of selector combs for attachment individually to the key bars of a telegraph sendingtape perforator, in combination with eight underlying bails, `aV group of code-element punches, meansv operable by one of the bails for perforating and.- feeding the tape, and means simultaneously operable by any four of the remaining seven bails forpreventing the actuation of corresponding code-element punches, each of said selector combs being adapted to engage with a predeterminedV and distinctive combination of precisely five of said bails. 'j j 4. Ina telegraph sending tape perforaton a keyboard having a plurality ofy key ,bars for selecting different code combinations toV be punched in the tape, thereby to characterize a desired uniform length code signal, and a selector comb mounted on each `of said key bars, each of said combs being conformed to a` pattern whereby aflxed number of'not less than three holesis punched' in response to any key 'manipulation and said number of holes bears an unequal'ratio to the number ofunpunched code-element-posi- .f VL". 5. A device fin accordance with claimA 4 and comprising a power bail andfajpluralityof code determining f bails, leach cooperatively4 disposed with respect, to ,different groups of selector'combs,

means under control ofV the "power bail 'forcaus- 75 Alill ing a sprocket feed hole to be punched, and an additional key bar having a selector comb mounted thereon, the last said comb being engageable with al1 of the baiis.

6. The method of producinga telegraph transmitting tape by meansy of a keyboard perforator, which comprises causing each character key depression to perforate an appropriate combination of code-element holes in a fixed number of positions arranged transversely of the tape, and causing the selected positions to be at least three in number and to be maintained in a constant 5 minority ratio to the available positions.

` JAMES A. SPENCER. 

